DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is adapted for use with a lid for the tank of a tank type electric vacuum cleaner, as in U.S. Patents 4,623,366, 4,508,550, or 4,185,974, each of which is incorporated herein by reference for its teachings with respect to vacuum cleaners and lids with filter cages. See also Fig. 5 herein.

In Figs. 1-4, the lid 10 of the vacuum cleaner 50 is shown inverted from its normal orientation of Fig. 5 over a vacuum cleaner collection tank 52. Its inverted orientation puts the lid in position for easier mounting of the filters. The lid includes the disk top 12 which is installed over the open top of a tank (not shown) to close the tank. The lid has an opening 14 in it that defines an air outlet from the tank through the lid. A blow motor 54 communicates with the outlet 14 for suctioning air therethrough and exhausting the air through outlet 56.

The conventional filter cage 20 comprises an upper band 22 secured at the underside of the disk 12 of the lid and the outlet 14 is defined in the disk 12, a bottom panel 24, which is a solid panel and a plurality of vertical struts 26 which are circumferentially spaced apart and arrayed around the filter cage 20 and extend between the band 22 and the panel 24, thereby defining a cage with a plurality of open spaces 27 between adjacent struts 26.

The panel 24 at the bottom of the cage and the band 22 around the top have approximately the same diameter. In that event, struts 26 are straight vertical. However, in typical embodiments of a filter cage, the struts 26 taper slightly inwardly because the bottom plate 24 is of slightly smaller external diameter than the band 22. The cage is thus slightly conical. The slight conicity does not diminish the effectiveness of the foam filtering cuff 30 described below as the foam cuff is sufficiently stretchable and elastic that it will securely wrap around the entire periphery of the cage defined by the struts 26, band 22 and panel 24. On the other hand, the below described ring 40 has its internal diameter determined by the widest diameter of the filter cage. But that is still sufficient to both stretch the filter paper of disk 36 tightly and to secure it in place with the ring 40 fully installed.

The tank 52 of the wet/dry pick up electric vacuum cleaner is capable of holding either collected dry materials or collected wet materials or even collected water sucked into the tank through inlet hose 58. The cage defines an enclosure for a float ball 29 which is held inside the cage by the lid 12, struts 26 and panel 24. The ball 29 closes the opening 14 when the ball floats up due to the tank being filled to a predetermined level by water. The height of the cage struts is selected so that sufficient area filtering surface is provided by the filter supported on the cage and to normally prevent the ball 29 from approaching too near to the inlet 14 during use of the vacuum cleaner.

During normal use of the vacuum cleaner when wet materials, e.g., wet dirt or even liquid which is dirty, dirty water, etc. are collected, the preferred filter medium for filtering any dirt which has not settled into the tank out of the air being suctioned through the outlet opening 14 is foam material. For this filtering purpose, a conventional foam material cuff 30 or a sleeve is in place over the cage struts 26 or is drawn into place there by the user. The foam cuff is of such length that it closes the space between the panel 24 and the band 22 and closes the opening spaces 27 between the struts 26 so that any wet material which is suctioned up toward the outlet 14 or which eventually rises in the tank to surround the foam cuff would be blocked by the foam material of the cuff from passing through the cuff and into the outlet.

The vacuum cleaner 50 with which the invention may be employed can at the option of the user be used for dry pick up purposes. As has been indicated, a foam cuff is not usually as useful for filtering dry materials as it is for filtering wet materials. A paper or cloth filter 35 is more desirable for dry material filtering. Hereafter, a paper filter alone is disclosed. But, a filter of cloth or of any other appropriate filter material may be used, wherein the filter material has adequate strength and flexibility, desired porosity and the other characteristics described below.

The paper filter 35 comprises a circular disk 36 of a diameter such that with the filter on top of the bottom panel 24 of the filter cage and the paper filter folded up along the foam sleeve over the cage, as shown in Fig. 4, the paper filter will extend over the full height of the filter cage to the board 22. The paper filter is a generally flat sheet of conventional filtering paper used in electric vacuum cleaners and the like, which is a relatively stiff yet flexible paper of the desired porosity to filter dry materials out of an air stream while permitting the air to flow through it to the outlet 14 through the tank lid.

For easing installation of the paper filter over the foam cuff 30 on the filter cage 20, the center of the filter paper disk 36 is marked, as by the central disk 38, and the user can place the marking 38 center over the panel 24 at the bottom of the cage for centering the disk 36.

For applying the paper filter disk over the foam cuff, the filter placement and securement ring 40 is provided. It is a ring of stiff, e.g. plastic, material having an interior 42 which is of a cross-section, and particularly a diameter, that is slightly greater than the cross-section or diameter of the filter cage at its widest end, e.g. at the band 22, but which is slightly narrower, for example, than the diameter of the foam cuff 30 when installed on the filter cage, so that when the ring 40 is drawn up over the foam sleeve, it will slightly depress the foam sleeve as it passes over it. This ensures that the paper disk is stretched tight and is also held securely in place while the foam cuff acts as a cushion and gasket to help make a non-leaky seal. A particular embodiment of vacuum cleaner may not use the foam cuff 30 or any other previously installed wet material filter. In that case, the diameter of the interior 42 of the ring is selected so as to be just slightly greater than the diameter of the widest part of the cage so that the ring will securely hold the paper filter to the cage.

The ring 40 has an upper leading end 44. That end is placed on top of the disk 36 and that end leads the movement of the ring 40 over the disk 35 for drawing the disk upward. The internal periphery of the leading end 44 is slightly flared outwardly that it can more easily slip over the disk 36, cuff 30 and panel 24 on the cage as the ring 40 is installed by drawing it over the cage.

To install the paper disk 36 over the foam cuff 30 and the cage 20, the ring 40 is first placed over the disk at the panel 24 and the ring is then pushed or pulled past the panel over the cuff 30 up along the struts 26. The paper disk is folded and drawn tightly up along the exterior of the foam cuff 30 and the cage 20 until the ring reaches the widest part of the cage at the top band 22 where the ring remains. The ring compresses the foam cuff 30 and squeezes the paper disk 36 against the band 22, and the entire until is held securely together. Additional fastening means are not required for holding the entire unit assembled.

Removal of the paper filter 35 involves simply moving the ring 40 down over and then off the filter cage and removing the filter 35. If desired, the foam sleeve or cuff 30 may also be removed and replaced.

Although the present invention has been described in connection with a preferred embodiment thereof, many other variations and modifications will now become apparent to those skilled in the art without departing from the scope of the invention. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.